DPF problem

[David1968]

Hi, I have a 2011 E220 CDI AMG Coupe, last year the engine management light came on, computer test identified high soot content in DPF, it was removed & cleaned, however every roughly 1k mls the engine management light comes back on, each time computer test identified high soot content in DPF high. Tbe garage performs a forced re gen, that works but again every 1k mls the engine management light comes on and car goes into limped mode, no other faults show up apart from DPS soot content high. Any advice would be much appreciated appreciated.

 

[Gazwould]

Small boost leak , dpf pressure sensor , egr sticking open slightly , thermostat , lack of or missed opportunies to regenerate etc .

 

[Dean Fletcher]

Any exhaust temp sensor. Strange no codes coming up. Is the car having diagnostic checks done with xentry? Or a generic OBD2 reader. Some fault codes don't come up with a cheaper Bluetooth device.

 

[alexanderfoti]

Small boost leak , dpf pressure sensor , egr sticking open slightly , thermostat , lack of or missed opportunies to regenerate etc .

+1 x common causes are boost leaks and injector faults

 

[David1968]

Thanks for the DPF replies, when tbe desiel specialist puts the computer on, it shows no other faults apart from soot content high in DPF, he does a re gen then the car runs great for about 1k mls then the engine management light came on then limp mode, no garage can tell me whats wrong.

 

[David1968]

Any exhaust temp sensor. Strange no codes coming up. Is the car having diagnostic checks done with xentry? Or a generic OBD2 reader. Some fault codes don't come up with a cheaper Bluetooth device.

Its a merc desiel specialist, he does a re gen then the car runs great for about 1k mls then the engine management light came on then limp mode.

 

[David1968]

Its a merc desiel specialist, he does a re gen then the car runs great for about 1k mls then the engine management light came on then limp mode.

Sorry, no other codes on.

 

[Wighty]

Sorry, no other codes on.

What sort of driving , distance/time length do you do in the car

 

[Mr Greedy]

I would normally expect 400-800 miles between regens depending on usage factors. 1,000 miles sounds like it could be very close to just not performing a regen.

You could buy and OBD2 Bluetooth dongle and a phone app like Torque Pro, and monitor exhaust temperature sensor. It needs to show above something like 600 degrees C for around 5-10 minutes if it's actually doing a regen. A pain to set the phone up every journey to check, and make sure it's safe and hands free before you start any journey, but could give you an answer.


Plus the leaks and injector faults already mentioned!

 

[David1968]

To be honest i dont do motorway driving however each week i go on the motorway and ooen it up, good for the DPF ive been told, i do about 1thousand mls per month.
No othe faults on the computer apart from DPF soot content high, 3 forced re gengs in 3 months & now its back to limp mode.

A mechanic said i could get the DPF opened & the contentsremoved, then have re mapping done.

Can this be done?

 

[David1968]

I have a 2011 E220CDI Coupe AMG 105k mls. Last year the engine management light came on then limp mode, computer test identified high soot content in DPF, it was taken out and cleaned.

Ive have the can 3yrs, no motorway driving, only do about 1k mls per month.

I do take in on the motorway every fortnight and ooen it up.

The garage has done 3 forced re gens but every roughly 1k mls it goes into limp mode.

No other faults come up apart from the high DPF soot content, its as if the cars not doing its own re gen.

Mechanic said he can take the DPF apart and re weld then get it mapped?

Think this is my only option.

Any advice.....

 

[David1968]

I have a 2011 E220CDI Coupe AMG 105k mls. Last year the engine management light came on then limp mode, computer test identified high soot content in DPF, it was taken out and cleaned.

Ive have the car 3yrs with no issued, no motorway driving, only do about 1k mls per month.

I do take in on the motorway every fortnight and open it up.

The garage has done 3 forced re gens in 3 months but roughly every 1k mls it goes into limp mode.

No other faults come up apart from the high DPF soot content, its as if the cars not doing its own re gen.

Ive taken it to a Merc dealer, they cant tell me what up, my own mechanic is a merc specalist, he cant find the fault, computer shows no other faults.

Mechanic said he can take the DPF apart and re weld then get it mapped?

Think this is my only option.

Any advice.....

 

[M80]

Assuming you're in the UK it's high risk.
Any sign of DPF tampering and you don't get an MOT.
Any future attempt at MOT will be seriously interrogated at a test.
Returning to stock would be high cost.

That ignores £1K fine if discovered.by plod.

There are going to be many of these situations while pillock politicians pretend to save the planet.

 

[th3h1ghlander]

I honestly don’t know much about this other than DPF maintenance regen only kicks in after about 15-20mins at motorway speeds. If you are doing 1k miles a month in a diesel on local roads it is possible it is genuinely getting clogged. I have been told that once they start coming up with blockage errors they are never really fully efficient again after being partially cleaned and regen’d. I know some OBDII diag devices can initiate a regen, may be worth getting one that supports the function and running the regen once every tank of fuel. Mostly IIRC the regen causes the dpf to get massively hot which is why it is done at high speed with lots of air passing to prevent damage to the car and whatever is under it (assume that it also requires engine input as well), I am not sure if OBDII devices can start a regen while driving but would be advisable if they can.
Another thought is perhaps something like the EGR is coked up and actually dropping chunks of soot into the exhaust system (is that even possible?) causing a blockage which is being detected at the dpf? Just shooting ideas at you. Tell me to shut up if it seems unreasonable


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[Donald McPherson]

What would happen if you (don't know if you even can) knock the inners of these things out to make it a straight through?

 

[LostKiwi]

What would happen if you (don't know if you even can) knock the inners of these things out to make it a straight through?

You make your car illegal and every possibility it won't pass an MOT, especially if more rigorous testing comes in (as is very likely given the current pro electric policies). Thousand pound fine if caught. Major fines for any garage doing it.
The DPF is there for a reason. It's to cut the crud that diesels pump into the atmosphere, in particular particulate matter that gets into the lungs and can cause respiratory illness and potentially cancer.
It's legally wrong and morally wrong.
If you don't want the hassle of DPFs buy a petrol car.

 

[Gazwould]

Always try and fix the route cause of the issue .

If there is not enough driving that's a different matter .

If you take the innerds out without adjusted software it will go into limp mode as the dpf pressure sensor detects too low a reading and tells the ecu it's detecting an exhaust leak .

People quote the car failing the mot all day long because that's all they understand , to understand like most things it's in the detail and these exhaust components are blind to the testers eye as covered by massive covers .

 

[LostKiwi]

these exhaust components are blind to the testers eye as covered by massive covers .

Not on all cars. It still doesn't make it undetectable. No DPF = more soot and that is detectable. It may not be tested at present but you can bet it will be.
Just running a finger around the tailpipe will show if it has a DPF. Black finger, no DPF, clean finger DPF fitted and working.

 

[Gazwould]

That's true but here and now we're talking about the Mercedes in question .

Mean average of 6 smoke opacity accelerations has to be below manufacturers smoke opacity coefficient as usually found on the main VIN sticker and that usually around 0.50 for a Euro 5 .

Both my diesels fast pass with one acceration and one is 18 years old Euro 3 with an unfair 0.60 manufacturer figure whereas the next model up to 2009 has 1.00 .

As for a new fangled test that's what they said pre May 2018 and I correctly predicted then they would tighten the smoke opacity test but even then it's flawed as you have the last of the non dpf cars
( 2009 ) Ford 1.8 tdci that have manufacturer smoke opacity value of 1.75 so by default is then tested to 1.50 whereas my 2003 Euro 3 1.9 tdi is tested to 0.60 and pre May 2018 the default was a massive 3.00 !

They are not going to change anything now with the ban on ice but may continue to threaten to do so .

 

[malcolm E53 AMG]

From my understanding of the DPF system the ECU is looking for two signals to initiate a regeneration is necessary, a high back pressure signal from one of the DPF exhaust sensors and secondly an indication from the thermostat that the engine is up to temperature so that’s where I’d focus my efforts. At your age of car I’d definitely start by changing the thermostat (MB stats usually fail >50k miles) followed by the sensors